Method and Apparatus for Tissue Ablation

ABSTRACT

The present application discloses devices that ablate human tissue. The device comprises a catheter with a shaft through which an ablative agent can travel, a liquid reservoir and a heating component, which may comprise a length of coiled tubing contained within a heating element, wherein activation of said heating element causes said coiled tubing to increase from a first temperature to a second temperature and wherein the increase causes a conversion of liquid within the coiled tubing to vapor, a reusable cord connecting the outlet of the reservoir to the inlet of the heating component, and a single use cord connecting a pressure-resistant inlet port of a vapor based ablation device to the outlet of the heating component.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a division application of U.S. patentapplication Ser. No. 15/400,759, entitled “Vapor Ablation System with aCatheter Having More Than One Positioning Element and Configured toTreat Pulmonary Tissue” and filed on Jan. 6, 2017, which is a divisionapplication of U.S. patent application Ser. No. 13/486,980, entitled“Method and Apparatus for Tissue Ablation”, filed on Jun. 1, 2012, andissued as U.S. Pat. No. 9,561,066 on Feb. 2, 2017, which is acontinuation in-part application of U.S. patent application Ser. No.12/573,939, of the same title and filed on Oct. 6, 2009, which relies onU.S. Provisional Patent Application No. 61/102,885, filed on Oct. 6,2008, for priority, all of which are herein incorporated by reference intheir entirety.

U.S. patent application Ser. No. 13/486,980 also relies on U.S.Provisional Patent Application No. 61/493,344, entitled “Method andApparatus for Tissue Ablation” and filed on Jun. 3, 2011, for priority,which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to medical apparatus and procedures. Moreparticularly, the present invention relates to a device for ablation oftissue comprising a centering or positioning attachment in order toposition the device at a consistent distance from the tissue to beablated.

BACKGROUND OF THE INVENTION

Colon polyps affect almost 25% of the population over the age of 50.While most polyps are detected on colonoscopy and easily removed using asnare, flat sessile polyps are hard to remove using the snare techniqueand carry a high risk of complications, such as bleeding andperforation. Recently, with improvement in imaging techniques, more flatpolyps are being detected. Endoscopically unresectable polyps requiresurgical removal. Most colon cancer arises from colon polyps and, safeand complete resection of these polyps is imperative for the preventionof colon cancer.

Barrett's esophagus is a precancerous condition effecting 10-14% of theUS population with gastro esophageal reflux disease (GERD) and is theproven precursor lesion of esophageal adenocarcinoma, the fastest risingcancer in the developed nations. The incidence of the cancer has risenover 6 fold in the last 2 decades and mortality has risen by 7 fold. The5-year mortality from esophageal cancer is 85%. Ablation of Barrett'sepithelium has shown to prevent its progression to esophageal cancer.

Dysfunctional uterine bleeding (DUB), or menorrhagia, affects 30% ofwomen in reproductive age. The associated symptoms have considerableimpact on a woman's health and quality of life. The condition istypically treated with endometrial ablation or a hysterectomy. The ratesof surgical intervention in these women are high. Almost 30% of women inthe US will undergo hysterectomy by the age of 60, with menorrhagia orDUB being the cause for surgery in 50-70% of these women. Endometrialablation techniques have been FDA approved for women with abnormaluterine bleeding and with intramural fibroids less than 2 cm. Thepresence of submucosal uterine fibroids and a large uterus size havebeen shown to decrease the efficacy of standard endometrial ablation. Ofthe five FDA approved global ablation devices (namely, Thermachoice,hydrothermal ablation, Novasure, Her Option, and microwave ablation)only microwave ablation (MEA) has been approved for use where thesubmucosal fibroids are less than 3 cm and are not occluding theendometrial cavity and, additionally, for large uteri up to 14 cm.

The known ablation treatments for Barrett's esophagus include lasertreatment (Ertan et al, Am. J. Gastro., 90:2201-2203 [1995]), ultrasonicablation (Bremner et al, Gastro. Endo., 43:6 [1996]), photodynamictherapy (PDT) using photo-sensitizer drugs (Overholt et al, Semin. Surq.Oncol., 1:372-376 (1995), multipolar electrocoagulation, such as by useof a bicap probe (Sampliner et al,), argon plasma coagulation (APC;),radiofrequency ablation (Sharma et al. Gastrointest Endosc) andcryoablation (Johnston et al. Gastrointest Endosc). The treatments aredelivered with the aid of an endoscope and devices passed through thechannel of the endoscope or alongside the endoscope.

Conventional techniques have inherent limitations, however, and have notfound widespread clinical applications. First, most of the hand heldablation devices (bicap probe, APC, cryoablation) are point and shootdevices that create small foci of ablation. This ablation mechanism isoperator dependent, cumbersome and time consuming. Second, because thetarget tissue is moving due to patient movement, respiration movement,normal peristalsis and vascular pulsations, the depth of ablation of thetarget tissue is inconsistent and results in a non-uniform ablation.Superficial ablation results in incomplete ablation with residualneoplastic tissue left behind. Deeper ablation results in complicationssuch as bleeding, stricture formation and perforation. All of theselimitations and complications have been reported with conventionaldevices.

For example, radiofrequency ablation uses a rigid bipolar balloon basedelectrode and radiofrequency thermal energy. The thermal energy isdelivered by direct contact of the electrode with the diseased Barrett'sepithelium allowing for a relatively uniform, large area ablation.However, the rigid electrode does not accommodate for variations inesophageal size and is ineffective in ablating lesions within a tortuousesophagus, proximal esophageal lesions as an esophagus narrows towardthe top, and lesions in the esophagus at the gastroesophageal junctiondue to changes in the esophageal diameter. Nodular disease in Barrett'sesophagus also cannot be treated using the rigid bipolar RF electrode.Due to its size and rigidity, the electrode cannot be passed through thescope. In addition, sticking of sloughed tissue to the electrode impedesdelivery of radiofrequency energy resulting in incomplete ablation. Theelectrode size is limited to 3 cm, thus requiring repeat applications totreat larger lengths of Barrett's esophagus.

Photodynamic therapy (PDT) is a two part procedure that involvesinjecting a photo-sensitizer that is absorbed and retained by theneoplastic and pre-neoplastic tissue. The tissue is then exposed to aselected wavelength of light which activates the photo-sensitizer andresults in tissue destruction. PDT is associated with complications suchas stricture formation and photo-sensitivity which has limited its useto the most advanced stages of the disease. In addition, patchy uptakeof the photosensitizer results in incomplete ablation and residualneoplastic tissue.

Cryoablation of the esophageal tissues via direct contact with liquidnitrogen has been studied in both animal models and humans (Rodgers etal, Cryobiology, 22:86-92 (1985); Rodgers et al, Ann. Thorac. Surq.55:52-7 [1983]) and has been used to treat Barrett's esophagus (Johnstonet al. Gastrointest Endosc) and early esophageal cancer (Grana et al,Int. Surg., 66:295 [1981]). A spray catheter that directly sprays liquidN₂ or CO₂ (cryoablation) or argon (APC) to ablate Barrett's tissue inthe esophagus has been described. These techniques suffer theshortcoming of the traditional hand-held devices. Treatment using thisprobe is cumbersome and requires operator control under directendoscopic visualization. Continuous movement in the esophagus due torespiration or cardiac or aortic pulsations or movement causes an unevendistribution of the ablative agent and results in non-uniform and/orincomplete ablation. Close or direct contact of the catheter to thesurface epithelium may cause deeper tissue injury, resulting inperforation, bleeding or stricture formation. Too distant a placement ofthe catheter due to esophageal movement will result in incompleteBarrett's ablation, requiring multiple treatment sessions or buriedlesions with a continued risk of esophageal cancer. Expansion ofcryogenic gas in the esophagus results in uncontrolled retching whichmay result in esophageal tear or perforation requiring continuedsuctioning of cryogen.

Colon polyps are usually resected using snare resection with or withoutthe use of monopolar cautery. Flat polyps or residual polyps after snareresection have been treated with argon plasma coagulation or lasertreatment. Both of these treatments are inadequate due to the previouslymentioned limitations. Hence, most large flat polyps undergo surgicalresection due to high risk of bleeding, perforation and residual diseaseusing traditional endoscopic resection or ablation techniques.

Most of the conventional balloon catheters traditionally used for tissueablation either heat or cool the balloon itself or a heating elementsuch as radio frequency (RF) coils mounted on the balloon. This requiresdirect contact of the balloon catheter with the ablated surface. Whenthe balloon catheter is deflated, the epithelium sticks to the catheterand sloughs off, thereby causing bleeding. Blood can interfere with thedelivery of energy, and therefore acts as an energy sink. In addition,reapplication of energy will result in deeper burn in the area wheresuperficial lining has sloughed. Further, balloon catheters cannot beemployed for treatment in non-cylindrical organs, like the uterus orsinuses, and also do not provide non-circumferential or focal ablationin a hollow organ. Additionally, if used with cryogens as ablativeagents, which expand exponentially upon being heated, balloon cathetersmay result in a closed cavity and trap the escape of cryogen, resultingin complications such as perforations and tears.

Accordingly, there is a need in the art for an improved method andsystem for delivering ablative agents to a tissue surface, for providinga consistent, controlled, and uniform ablation of the target tissue, andfor minimizing the adverse side effects of introducing ablative agentsinto a patient.

SUMMARY OF THE INVENTION

In one embodiment, the present specification discloses a device to beused in conjunction with a tissue ablation system, comprising: a handlewith a pressure-resistant port on its distal end, a flow channel throughwhich an ablative agent can travel, and one or more connection ports onits proximal end for the inlet of said ablative agent and for an RFfeed; an insulated catheter that attaches to said pressure-resistantport of said snare handle, containing a shaft through which an ablativeagent can travel and one or more ports along its length for the releaseof said ablative agent; and one or more positioning elements attached tosaid catheter shaft at one or more separate positions, wherein saidpositioning element(s) is configured to position said catheter at apredefined distance from the tissue to be ablated.

Optionally, the handle has one pressure-resistant port for theattachment of both an ablative agent inlet and an RF feed. The handlehas one separate pressure-resistant port for the attachment of anablative agent inlet and one separate port for the attachment of an RFfeed or an electrical feed.

In another embodiment, the present specification discloses a device tobe used in conjunction with a tissue ablation system, comprising: ahandle with a pressure-resistant port on its distal end, a flow channelpassing through said handle which is continuous with a pre-attached cordthrough which an ablative agent can travel, and a connection port on itsproximal end for an RF feed or an electrical field; an insulatedcatheter that attaches to said pressure-resistant port of said handle,containing a shaft through which an ablative agent can travel and one ormore ports along its length for the release of said ablative agent; andone or more positioning elements attached to said catheter shaft at oneor more separate positions, wherein said positioning element(s) isconfigured to position said catheter at a predefined distance from thetissue to be ablated. Optionally, the distal end of said catheter isdesigned to puncture the target.

In another embodiment, the present specification discloses a device tobe used in conjunction with a tissue ablation system, comprising: anesophageal probe with a pressure-resistant port on its distal end, aflow channel through which an ablative agent can travel, and one or moreconnection ports on its proximal end for the inlet of said ablativeagent and for an RF feed or an electrical feed; an insulated catheterthat attaches to said pressure-resistant port of said esophageal probe,containing a shaft through which an ablative agent can travel and one ormore ports along its length for the release of said ablative agent; andone or more inflatable positioning balloons at either end of saidcatheter positioned beyond said one or more ports, wherein saidpositioning balloons are configured to position said catheter at apredefined distance from the tissue to be ablated.

Optionally, the catheter is dual lumen, wherein a first lumenfacilitates the transfer of ablative agent and a second lumen containsan electrode for RF ablation. The catheter has differential insulationalong its length.

The present specification is also directed toward a tissue ablationdevice, comprising: a liquid reservoir, wherein said reservoir includesan outlet connector that can resist at least 1 atm of pressure for theattachment of a reusable cord; a heating component comprising: a lengthof coiled tubing contained within a heating element, wherein activationof said heating element causes said coiled tubing to increase from afirst temperature to a second temperature and wherein said increasecauses a conversion of liquid within said coiled tubing to vapor; and aninlet connected to said coiled tubing; an outlet connected to saidcoiled tubing; and at least one pressure-resistant connection attachedto the inlet and/or outlet; a cord connecting the outlet of saidreservoir to the inlet of the heating component; a single use cordconnecting a pressure-resistant inlet port of a vapor based ablationdevice to the outlet of said heating component.

In one embodiment, the liquid reservoir is integrated within anoperating room equipment generator. In one embodiment, the liquid iswater and the vapor is steam.

In one embodiment, the pressure-resistant connections are luer lockconnections. In one embodiment, the coiled tubing is copper.

In one embodiment, the tissue ablation device further comprises a footpedal, wherein only when said foot pedal is pressed, vapor is generatedand passed into said single use cord. In another embodiment, only whenpressure is removed from said foot pedal, vapor is generated and passedinto said single use cord.

In another embodiment, the present specification discloses a vaporablation system used for supplying vapor to an ablation device,comprising; a single use sterile fluid container with attachedcompressible tubing used to connect the fluid source to a heating unitin the handle of a vapor ablation catheter. The tubing passes through apump that delivers the fluid into the heating unit at a predeterminedspeed. There is present a mechanism such as a unidirectional valvebetween the fluid container and the heating unit to prevent the backflowof vapor from the heating unit. The heating unit is connected to theablation catheter to deliver the vapor from the heating unit to theablation site. The flow of vapor is controlled by a microprocessor. Themicroprocessor uses a pre-programmed algorithm in an open-loop system oruses information from one or more sensors incorporated in the ablationsystem in a closed-loop system or both to control delivery of vapor.

In one embodiment the handle of the ablation device is made of athermally insulating material to prevent thermal injury to the operator.The heating unit is enclosed in the handle. The handle locks into thechannel of an endoscope after the catheter is passed through the channelof the endoscope. The operator can than manipulate the catheter byholding the insulated handle or by manipulating the catheter proximal tothe insulating handle.

The present specification is also directed toward a vapor ablationsystem comprising: a container with a sterile liquid therein; a pump influid communication with said container; a first filter disposed betweenand in fluid communication with said container and said pump; a heatingcomponent in fluid communication with said pump; a valve disposedbetween and in fluid communication with said pump and heating container;a catheter in fluid communication with said heating component, saidcatheter comprising at least one opening at its operational end; and, amicroprocessor in operable communication with said pump and said heatingcomponent, wherein said microprocessor controls the pump to control aflow rate of the liquid from said container, through said first filter,through said pump, and into said heating component, wherein said liquidis converted into vapor via the transfer of heat from said heatingcomponent to said fluid, wherein said conversion of said fluid into saidvapor results is a volume expansion and a rise in pressure where saidrise in pressure forces said vapor into said catheter and out said atleast one opening, and wherein a temperature of said heating componentis controlled by said microprocessor.

In one embodiment, the vapor ablation system further comprises at leastone sensor on said catheter, wherein information obtained by said sensoris transmitted to said microprocessor, and wherein said information isused by said microprocessor to regulate said pump and said heatingcomponent and thereby regulate vapor flow. In one embodiment, the atleast one sensor includes one or more of a temperature sensor, flowsensor, or pressure sensor.

In one embodiment, the vapor ablation system further comprises a screwcap on said liquid container and a puncture needle on said first filter,wherein said screw cap is punctured by said puncture needle to providefluid communication between said container and said first filter.

In one embodiment, the liquid container and catheter are disposable andconfigured for a single use.

In one embodiment, the fluid container, first filter, pump, heatingcomponent, and catheter are connected by sterile tubing and theconnections between said pump and said heating component and saidheating component and said catheter are pressure resistant.

The present specification is also directed toward a tissue ablationsystem comprising: a catheter with a proximal end and a distal end and alumen therebetween, said catheter comprising: a handle proximate theproximal end of said catheter and housing a fluid heating chamber and aheating element enveloping said chamber, a wire extending distally fromsaid heating element and leading to a controller; an insulating sheathextending and covering the length of said catheter and disposed betweensaid handle and said heating element at said distal end of saidcatheter; and, at least one opening proximate the distal end of saidcatheter for the passage of vapor; and, a controller operably connectedto said heating element via said wire, wherein said controller iscapable of modulating energy supplied to said heating element andfurther wherein said controller is capable of adjusting a flow rate ofliquid supplied to said catheter; wherein liquid is supplied to saidheating chamber and then converted to vapor within said heating chamberby a transfer of heat from said heating element to said chamber, whereinsaid conversion of said liquid to vapor results in a volume expansionand a rise in pressure within said catheter, and wherein said rise inpressure pushes said vapor through said catheter and out said at leastone opening.

In one embodiment, the tissue ablation system further comprises apressure resistant fitting attached to the fluid supply and a one-wayvalve in said pressure resistant fitting to prevent a backflow of vaporinto the fluid supply.

In one embodiment, the tissue ablation system further comprises at leastone sensor on said catheter, wherein information obtained by said sensoris transmitted to said microprocessor, and wherein said information isused by said microprocessor to regulate said pump and said heatingcomponent and thereby regulate vapor flow.

In one embodiment, the tissue ablation system further comprises a metalframe within said catheter, wherein said metal frame is in thermalcontact with said heating chamber and conducts heat to said catheterlumen, thereby preventing condensation of said vapor. In variousembodiments, the metal frame comprises a metal skeleton with outwardlyextending fins at regularly spaced intervals, a metal spiral, or a metalmesh and the metal frame comprises at least one of copper, stainlesssteel, or another ferric material.

In one embodiment, the heating element comprises a heating block,wherein said heating block is supplied power by said controller.

In various embodiments, the heating element uses one of magneticinduction, microwave, high intensity focused ultrasound, or infraredenergy to heat said heating chamber and the fluid therein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will befurther appreciated, as they become better understood by reference tothe detailed description when considered in connection with theaccompanying drawings, wherein:

FIG. 1 illustrates an ablation device, in accordance with an embodimentof the present invention;

FIG. 2A illustrates a longitudinal section of an ablation device withports distributed thereon;

FIG. 2B illustrates a cross section of a port on the ablation device, inaccordance with an embodiment of the present invention;

FIG. 2C illustrates a cross section of a port on the ablation device, inaccordance with another embodiment of the present invention;

FIG. 2D illustrates a catheter of the ablation device, in accordancewith an embodiment of the present invention;

FIG. 2E illustrates an ablation device in the form of a catheterextending from a conventional snare handle, in accordance with anembodiment of the present invention;

FIG. 2F illustrates a cross section of an ablation device in the form ofa catheter extending from a conventional snare handle with apre-attached cord, in accordance with another embodiment of the presentinvention;

FIG. 2G illustrates an ablation device in the form of a catheterextending from a conventional esophageal probe, in accordance with anembodiment of the present invention;

FIG. 3A illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with an embodiment of the presentinvention;

FIG. 3B illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with another embodiment of thepresent invention;

FIG. 3C is a flowchart illustrating the basic procedural steps for usingthe ablation device, in accordance with an embodiment of the presentinvention;

FIG. 4A illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with an embodiment of the presentinvention;

FIG. 4B illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with another embodiment of the presentinvention;

FIG. 5A illustrates the ablation device with a coaxial catheter design,in accordance with an embodiment of the present invention;

FIG. 5B illustrates a partially deployed positioning device, inaccordance with an embodiment of the present invention;

FIG. 5C illustrates a completely deployed positioning device, inaccordance with an embodiment of the present invention;

FIG. 5D illustrates the ablation device with a conical positioningelement, in accordance with an embodiment of the present invention;

FIG. 5E illustrates the ablation device with a disc shaped positioningelement, in accordance with an embodiment of the present invention;

FIG. 6 illustrates an upper gastrointestinal tract with a bleedingvascular lesion being treated by the ablation device, in accordance withan embodiment of the present invention;

FIG. 7 illustrates endometrial ablation being performed in a femaleuterus by using the ablation device, in accordance with an embodiment ofthe present invention;

FIG. 8 illustrates sinus ablation being performed in a nasal passage byusing the ablation device, in accordance with an embodiment of thepresent invention;

FIG. 9 illustrates bronchial and bullous ablation being performed in apulmonary system by using the ablation device, in accordance with anembodiment of the present invention;

FIG. 10 illustrates prostate ablation being performed on an enlargedprostrate in a male urinary system by using the device, in accordancewith an embodiment of the present invention;

FIG. 11 illustrates fibroid ablation being performed in a female uterusby using the ablation device, in accordance with an embodiment of thepresent invention;

FIG. 12 illustrates a vapor delivery system using an RF heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention;

FIG. 13 illustrates a vapor delivery system using a resistive heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention;

FIG. 14 illustrates a vapor delivery system using a heating coil forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention;

FIG. 15 illustrates the heating component and coiled tubing of theheating coil vapor delivery system of FIG. 14, in accordance with anembodiment of the present invention;

FIG. 16A illustrates the unassembled interface connection between theablation device and the single use cord of the heating coil vapordelivery system of FIG. 14, in accordance with an embodiment of thepresent invention;

FIG. 16B illustrates the assembled interface connection between theablation device and the single use cord of the heating coil vapordelivery system of FIG. 14, in accordance with an embodiment of thepresent invention;

FIG. 17 illustrates a vapor ablation system using a heater or heatexchange unit for supplying vapor to the ablation device, in accordancewith another embodiment of the present invention;

FIG. 18 illustrates the fluid container, filter member, and pump of thevapor ablation system of FIG. 17;

FIG. 19 illustrates a first view of the fluid container, filter member,pump, heater or heat exchange unit, and microcontroller of the vaporablation system of FIG. 17;

FIG. 20 illustrates a second view of the fluid container, filter member,pump, heater or heat exchange unit, and microcontroller of the vaporablation system of FIG. 17;

FIG. 21 illustrates the unassembled filter member of the vapor ablationsystem of FIG. 17, depicting the filter positioned within;

FIG. 22 illustrates one embodiment of the microcontroller of the vaporablation system of FIG. 17;

FIG. 23 illustrates one embodiment of a catheter assembly for use withthe vapor ablation system of FIG. 17;

FIG. 24 illustrates one embodiment of a heat exchange unit for use withthe vapor ablation system of FIG. 17;

FIG. 25 illustrates another embodiment of a heat exchange unit for usewith the vapor ablation system of the present invention;

FIG. 26 illustrates the use of induction heating to heat a chamber;

FIG. 27A illustrates one embodiment of a coil used with inductionheating in the vapor ablation system of the present invention;

FIG. 27B illustrates one embodiment of a catheter handle used withinduction heating in the vapor ablation system of the present invention;

FIG. 28A is a front view cross sectional diagram illustrating oneembodiment of a catheter used with induction heating in the vaporablation system of the present invention;

FIG. 28B is a longitudinal view cross sectional diagram illustrating oneembodiment of a catheter used with induction heating in the vaporablation system of the present invention;

FIG. 28C is a longitudinal view cross sectional diagram illustratinganother embodiment of a catheter with a metal spiral used with inductionheating in the vapor ablation system of the present invention;

FIG. 28D is a longitudinal view cross sectional diagram illustratinganother embodiment of a catheter with a mesh used with induction heatingin the vapor ablation system of the present invention; and,

FIG. 29 illustrates one embodiment of a heating unit using microwaves toconvert fluid to vapor in the vapor ablation system of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed toward an ablation device comprising acatheter with one or more centering or positioning attachments at one ormore ends of the catheter to affix the catheter and its infusion port ata fixed distance from the ablative tissue which is not affected by themovements of the organ. The arrangement of one or more spray portsallows for uniform spray of the ablative agent producing a uniformablation of a large area, such as encountered in Barrett's esophagus.The flow of ablative agent is controlled by the microprocessor anddepends upon one or more of the length or area of tissue to be ablated,type and depth of tissue to be ablated, and distance of the infusionport from or in the tissue to be ablated.

The present invention is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: a handle with apressure-resistant port on its distal end, a flow channel through whichan ablative agent can travel, and one or more connection ports on itsproximal end for the inlet of said ablative agent and for an RF feed oran electrical feed; an insulated catheter that attaches to saidpressure-resistant port of said handle, containing a shaft through whichan ablative agent can travel and one or more ports along its length forthe release of said ablative agent; and, one or more positioningelements attached to said catheter shaft at one or more separatepositions, wherein said positioning element(s) is configured to positionsaid catheter at a predefined distance from or in the tissue to beablated.

In one embodiment, the handle has one pressure-resistant port for theattachment of both an ablative agent inlet and an RF feed. In anotherembodiment, the handle has one separate pressure-resistant port for theattachment of an ablative agent inlet and one separate port for theattachment of an RF feed or an electrical feed.

The present invention is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: a handle with apressure-resistant port on its distal end, a flow channel passingthrough said handle which is continuous with a pre-attached cord throughwhich an ablative agent can travel, and a connection port on itsproximal end for an RF feed or an electrical feed; an insulated catheterthat attaches to said pressure-resistant port of said handle, containinga shaft through which an ablative agent can travel and one or more portsalong its length for the release of said ablative agent; and, one ormore positioning elements attached to said catheter shaft at one or moreseparate positions, wherein said positioning element(s) is configured toposition said catheter at a predefined distance from or in the tissue tobe ablated. In one embodiment, the distal end of said catheter isdesigned to puncture the target tissue to deliver ablative agent to thecorrect depth and location.

The present invention is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: an esophagealprobe with a pressure-resistant port on its distal end, a flow channelthrough which an ablative agent can travel, and one or more connectionports on its proximal end for the inlet of said ablative agent and foran RF feed; an insulated catheter that attaches to saidpressure-resistant port of said esophageal probe, containing a shaftthrough which an ablative agent can travel and one or more ports alongits length for the release of said ablative agent; and, one or moreinflatable positioning balloons at either end of said catheterpositioned beyond said one or more ports, wherein said positioningballoons are configured to position said catheter at a predefineddistance from the tissue to be ablated.

In one embodiment, the catheter is dual lumen, wherein a first lumenfacilitates the transfer of ablative agent and a second lumen containsan electrode for RF ablation.

In one embodiment, the catheter has differential insulation along itslength.

The present invention is also directed toward a vapor delivery systemused for supplying vapor to an ablation device, comprising: a liquidreservoir, wherein said reservoir includes a pressure-resistant outletconnector for the attachment of a reusable cord; a reusable cordconnecting the outlet of said reservoir to the inlet of a heatingcomponent; a powered heating component containing a length of coiledtubing within for the conversion of liquid to vapor andpressure-resistant connections on both the inlet and outlet ends of saidheating component; and, a single use cord connecting apressure-resistant inlet port of a vapor based ablation device to theoutlet of said heating component.

In one embodiment, the liquid reservoir is integrated within anoperating room equipment generator.

In one embodiment, the liquid is water and resultant said vapor issteam.

In one embodiment, the pressure-resistant connections are of a luer locktype.

In one embodiment, the coiled tubing is copper.

In one embodiment, the vapor delivery system used for supplying vapor toan ablation device further comprises a foot pedal used by the operatorto deliver more vapor to the ablation device.

“Treat,” “treatment,” and variations thereof refer to any reduction inthe extent, frequency, or severity of one or more symptoms or signsassociated with a condition.

“Duration” and variations thereof refer to the time course of aprescribed treatment, from initiation to conclusion, whether thetreatment is concluded because the condition is resolved or thetreatment is suspended for any reason. Over the duration of treatment, aplurality of treatment periods may be prescribed during which one ormore prescribed stimuli are administered to the subject.

“Period” refers to the time over which a “dose” of stimulation isadministered to a subject as part of the prescribed treatment plan.

The term “and/or” means one or all of the listed elements or acombination of any two or more of the listed elements.

The terms “comprises” and variations thereof do not have a limitingmeaning where these terms appear in the description and claims.

Unless otherwise specified, “a,” “an,” “the,” “one or more,” and “atleast one” are used interchangeably and mean one or more than one.

For any method disclosed herein that includes discrete steps, the stepsmay be conducted in any feasible order. And, as appropriate, anycombination of two or more steps may be conducted simultaneously.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc.). Unless otherwise indicated, all numbersexpressing quantities of components, molecular weights, and so forthused in the specification and claims are to be understood as beingmodified in all instances by the term “about.” Accordingly, unlessotherwise indicated to the contrary, the numerical parameters set forthin the specification and claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. All numerical values, however, inherently contain a rangenecessarily resulting from the standard deviation found in theirrespective testing measurements.

Ablative agents such as steam, heated gas or cryogens, such as, but notlimited to, liquid nitrogen are inexpensive and readily available andare directed via the infusion port onto the tissue, held at a fixed andconsistent distance, targeted for ablation. This allows for uniformdistribution of the ablative agent on the targeted tissue. The flow ofthe ablative agent is controlled by a microprocessor according to apredetermined method based on the characteristic of the tissue to beablated, required depth of ablation, and distance of the port from thetissue. The microprocessor may use temperature, pressure or othersensing data to control the flow of the ablative agent. In addition, oneor more suction ports are provided to suction the ablation agent fromthe vicinity of the targeted tissue. The targeted segment can be treatedby a continuous infusion of the ablative agent or via cycles of infusionand removal of the ablative agent as determined and controlled by themicroprocessor.

It should be appreciated that the devices and embodiments describedherein are implemented in concert with a controller that comprises amicroprocessor executing control instructions. The controller can be inthe form of any computing device, including desktop, laptop, and mobiledevice, and can communicate control signals to the ablation devices inwired or wireless form.

The present invention is directed towards multiple embodiments. Thefollowing disclosure is provided in order to enable a person havingordinary skill in the art to practice the invention. Language used inthis specification should not be interpreted as a general disavowal ofany one specific embodiment or used to limit the claims beyond themeaning of the terms used therein. The general principles defined hereinmay be applied to other embodiments and applications without departingfrom the spirit and scope of the invention. Also, the terminology andphraseology used is for the purpose of describing exemplary embodimentsand should not be considered limiting. Thus, the present invention is tobe accorded the widest scope encompassing numerous alternatives,modifications and equivalents consistent with the principles andfeatures disclosed. For purpose of clarity, details relating totechnical material that is known in the technical fields related to theinvention have not been described in detail so as not to unnecessarilyobscure the present

FIG. 1 illustrates an ablation device, in accordance with an embodimentof the present invention. The ablation device comprises a catheter 10having a distal centering or positioning attachment which is aninflatable balloon 11. The catheter 10 is made of or covered with aninsulated material to prevent the escape of ablative energy from thecatheter body. The ablation device comprises one or more infusion ports12 for the infusion of ablative agent and one or more suction ports 13for the removal of ablative agent. In one embodiment, the infusion port12 and suction port 13 are the same. In one embodiment, the infusionports 12 can direct the ablative agent at different angles. Ablativeagent is stored in a reservoir 14 connected to the catheter 10. Deliveryof the ablative agent is controlled by a microprocessor 15 andinitiation of the treatment is controlled by a treating physician usingan input device, such as a foot-paddle 16. In other embodiments, theinput device could be a voice recognition system (that is responsive tocommands such as “start”, “more”, “less”, etc.), a mouse, a switch,footpad, or any other input device known to persons of ordinary skill inthe art. In one embodiment, microprocessor 15 translates signals fromthe input device, such as pressure being placed on the foot-paddle orvocal commands to provide “more” or “less” ablative agent, into controlsignals that determine whether more or less ablative agent is dispensed.Optional sensor 17 monitors changes in an ablative tissue or itsvicinity to guide flow of ablative agent. In one embodiment, optionalsensor 17 also includes a temperature sensor. Optional infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensors18 measure the dimensions of the hollow organ.

In one embodiment, a user interface included with the microprocessor 15allows a physician to define device, organ, and condition which in turncreates default settings for temperature, cycling, volume (sounds), andstandard RF settings. In one embodiment, these defaults can be furthermodified by the physician. The user interface also includes standarddisplays of all key variables, along with warnings if values exceed orgo below certain levels.

The ablation device also includes safety mechanisms to prevent usersfrom being burned while manipulating the catheter, including insulation,and optionally, cool air flush, cool water flush, and alarms/tones toindicate start and stop of treatment.

In one embodiment, the inflatable balloon has a diameter of between 1 mmand 10 cm. In one embodiment, the inflatable balloon is separated fromthe ports by a distance of 1 mm to 10 cm. In one embodiment, the size ofthe port openings is between 1 μm and 1 cm. It should be appreciatedthat the inflatable balloon is used to fix the device and therefore isconfigured to not contact the ablated area. The inflatable balloon canbe any shape that contacts the hollow organ at 3 or more points. One ofordinary skill in the art will recognize that, using triangulation, onecan calculate the distance of the catheter from the lesion.Alternatively, the infrared, electromagnetic, acoustic or radiofrequencyenergy emitters and sensors 18 can measure the dimensions of the holloworgan. The infrared, electromagnetic, acoustic or radiofrequency energyis emitted from the emitter 18 and is reflected back from the tissue tothe detector in the emitter 18. The reflected data can be used todetermine the dimension of the hollow cavity. It should be appreciatedthat the emitter and sensor 18 can be incorporated into a singletransceiver that is capable of both emitting energy and detecting thereflected energy.

FIG. 2A illustrates a longitudinal section of the ablation device,depicting a distribution of infusion ports. FIG. 2B illustrates a crosssection of a distribution of infusion ports on the ablation device, inaccordance with an embodiment of the present invention. The longitudinaland cross sectional view of the catheter 10 as illustrated in FIGS. 2Aand 2B respectively, show one arrangement of the infusion ports 12 toproduce a uniform distribution of ablative agent 21 (shown in FIG. 2B)in order to provide a circumferential area of ablation in a hollow organ20. FIG. 2C illustrates a cross section of a distribution of infusionports on the ablation device, in accordance with another embodiment ofthe present invention. The arrangement of the infusion ports 12 asillustrated in FIG. 2C produce a focal distribution of ablative agent 21and a focal area of ablation in a hollow organ 20.

For all embodiments described herein, it should be appreciated that thesize of the port, number of ports, and distance between the ports willbe determined by the volume of ablative agent needed, pressure that thehollow organ can withstand, size of the hollow organ as measured by thedistance of the surface from the port, length of the tissue to beablated (which is roughly the surface area to be ablated),characteristics of the tissue to be ablated and depth of ablationneeded. In one embodiment, there is at least one port opening that has adiameter between 1 μm and 1 cm. In another embodiment, there are two ormore port openings that have a diameter between 1 μm and 1 cm and thatare equally spaced around the perimeter of the device.

FIG. 2D illustrates another embodiment of the ablation device. The vaporablation catheter comprises an insulated catheter 21 with one or morepositioning attachments 22 of known length 23. The vapor ablationcatheter has one or more vapor infusion ports 25. The length 24 of thevapor ablation catheter 21 with infusion ports 25 is determined by thelength or area of the tissue to be ablated. Vapor 29 is deliveredthrough the vapor infusion ports 25. The catheter 21 is preferablypositioned in the center of the positioning attachment 22, and theinfusion ports 25 are arranged circumferentially for circumferentialablation and delivery of vapor. In another embodiment, the catheter 21can be positioned toward the periphery of the positioning attachment 22and the infusion ports 25 can be arranged non-circumferentially,preferably linearly on one side for focal ablation and delivery ofvapor. The positioning attachment 22 is one of an inflatable balloon, awire mesh disc with or without an insulated membrane covering the disc,a cone shaped attachment, a ring shaped attachment or a freeformattachment designed to fit the desired hollow body organ or hollow bodypassage, as further described below. Optional infrared, electromagnetic,acoustic or radiofrequency energy emitters and sensors 28 areincorporated to measure the dimensions of the hollow organ.

The vapor ablation catheter may also comprise an optional coaxial sheet27 to restrain the positioning attachment 22 in a manner comparable to acoronary metal stent. In one embodiment, the sheet is made of memorymetal or memory material with a compressed linear form and anon-compressed form in the shape of the positioning attachment.Alternatively, the channel of an endoscope may perform the function ofrestraining the positioning attachment 22 by, for example, acting as aconstraining sheath. Optional sensor 26 is deployed on the catheter tomeasure changes associated with vapor delivery or ablation. The sensoris one of temperature, pressure, photo or chemical sensor.

Optionally, one or more, infrared, electromagnetic, acoustic orradiofrequency energy emitters and sensors 28 can measure the dimensionsof the hollow organ. The infrared, electromagnetic, acoustic orradiofrequency energy is emitted from the emitter 28 and is reflectedback from the tissue to the detector in the emitter 28. The reflecteddata can be used to determine the dimension of the hollow cavity. Themeasurement is performed at one or multiple points to get an accurateestimate of the dimension of the hollow organ. The data can also be usedto create a topographic representation of the hollow organ. Additionaldata from diagnostic tests can be used to validate or add to the datafrom the above measurements.

FIG. 2E illustrates an ablation device 220 in the form of a catheter 221extending from a conventional handle 222, in accordance with anembodiment of the present invention. The catheter 221 is of a type asdescribed above and extends from and attaches to the handle 222. In oneembodiment, the catheter 221 is insulated to protect the user from burnsthat could result from hot vapor heating the catheter. In oneembodiment, the catheter is composed of a material that will ensure thatthe outer temperature of the catheter will remain below 60° C. duringuse. The handle 222 includes a pressure resistant port at the point ofattachment with the catheter 221. The handle 222 also includes a flowchannel within that directs vapor through to the catheter 221.

In one embodiment, the snare handle 222 includes a single attachmentport 223 for the connection of a vapor stream and an RF feed. In anotherembodiment (not shown), the snare handle includes two separateattachment ports for the connection of a vapor stream and an RF feed.The attachment port 223 interfaces with the vapor supply cord viapressure-resistant connectors. In one embodiment, the connectors are ofa luer lock type. In one embodiment, the catheter 221 is a dual lumencatheter. The first lumen serves to deliver vapor to the site ofablation. In one embodiment, the vapor is released through small ports224 positioned proximate the distal end of the catheter 221. The distalend of the catheter 221 is designed so that it can puncture the tissueto deliver vapor to the desired depth and location within the targettissue. In one embodiment, the distal end of the catheter 221 tapers toa point. The second lumen houses the electrode used for RF ablation. Inone embodiment, the delivery of vapor or RF waves is achieved throughthe use of a microprocessor. In another embodiment, the user can releasevapor or subject the target tissue to RF waves by the use of actuators(not shown) on the handle 222. In one embodiment, the catheter hasvarying or differential insulation along its length. In one embodiment,the ablation device 220 includes a mechanism in which a snare to graspthe tissue to be ablated and sizing the tissue in the snare is used todetermine the amount of vapor to be delivered.

FIG. 2F illustrates a cross section of an ablation device 227 in theform of a catheter 231 extending from a conventional handle 232 with apre-attached cord 235, in accordance with another embodiment of thepresent invention. The cord 235 attaches directly to the vapor deliverysystem, eliminating one interface between the system and the ablationdevice and thereby decreasing the chance of system failure as a resultof disconnection. In this embodiment, the handle 232 includes a separateattachment port (not shown) for the RF or an electric feed.

FIG. 2G illustrates an ablation device 229 in the form of a catheter 241extending from a conventional esophageal probe 226, in accordance withan embodiment of the present invention. In one embodiment, the catheter241 is insulated and receives vapor from a flow channel contained withinthe probe 226. The catheter 241 includes a multitude of small ports 244for the delivery of vapor to the target tissue. The delivery of vapor iscontrolled by a microprocessor. In one embodiment, the catheter 241 alsoincludes two inflatable balloons 228, one at its distal end beyond thelast vapor port 244, and one at its proximal end, proximate thecatheter's 241 attachment to the probe 226. All vapor ports arepositioned between these two balloons. Once the device 229 is insertedwithin the esophagus, the balloons 228 are inflated to keep the catheter241 positioned and to contain the vapor within the desired treatmentarea. In one embodiment, the balloons must be separated from theablation region by a distance of greater than 0 mm, preferably 1 mm andideally 1 cm. In one embodiment, the diameter of each balloon wheninflated is in the range of 10 to 100 mm, preferably 15-40 mm, althoughone of ordinary skill in the art would appreciate that the precisedimensions are dependent on the size of the patient's esophagus.

In one embodiment, the catheter 241 attached to the esophageal probe 226is a dual lumen catheter. The first lumen serves to deliver vapor to thesite of ablation as described above. The second lumen houses theelectrode used for RF ablation.

FIG. 3A illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with an embodiment of the presentinvention. The upper gastrointestinal tract comprises Barrett'sesophagus 31, gastric cardia 32, gastroesophageal junction 33 anddisplaced squamo-columnar junction 34. The area between thegastroesophageal junction 33 and the displaced squamo-columnar junction34 is Barrett's esophagus 31, which is targeted for ablation. Distal tothe cardia 32 is the stomach 35 and proximal to the cardia 32 is theesophagus 36. The ablation device is passed into the esophagus 36 andthe positioning device 11 is placed in the gastric cardia 32 abuttingthe gastroesophageal junction 33. This affixes the ablation catheter 10and its ports 12 in the center of the esophagus 36 and allows foruniform delivery of the ablative agent 21 to the Barrett's esophagus 31.

In one embodiment, the positioning device is first affixed to ananatomical structure, not being subjected to ablation, before ablationoccurs. Where the patient is undergoing circumferential ablation orfirst time ablation, the positioning attachment is preferably placed inthe gastric cardia, abutting the gastroesophageal junction. Where thepatient is undergoing a focal ablation of any residual disease, it ispreferable to use the catheter system shown in FIG. 4B, as discussedbelow. In one embodiment, the positioning attachment must be separatedfrom the ablation region by a distance of greater than 0 mm, preferably1 mm and ideally 1 cm. In one embodiment, the size of the positioningdevice is in the range of 10 to 100 mm, preferably 20-40 mm, althoughone of ordinary skill in the art would appreciate that the precisedimensions are dependent on the size of the patient's esophagus.

The delivery of ablative agent 21 through the infusion port 12 iscontrolled by the microprocessor 15 coupled with the ablation device.The delivery of ablative agent is guided by predetermined programmaticinstructions, depending on the tissue to be ablated and the depth ofablation required. In one embodiment, the target procedural temperaturewill need to be between −100 degrees Celsius and 200 degrees Celsius,preferably between 50 degrees Celsius and 75 degrees Celsius, as furthershown in the dosimetery table below. In one embodiment, esophagealpressure should not exceed 5 atm, and is preferably below 0.5 atm. Inone embodiment, the target procedural temperature is achieved in lessthan 1 minute, preferably in less than 5 seconds, and is capable ofbeing maintained for up to 10 minutes, preferably 1 to 10 seconds, andthen cooled to body temperature. One of ordinary skill in the art wouldappreciate that the treatment can be repeated until the desired ablationeffect is achieved.

Optional sensor 17 monitors intraluminal parameters such as temperatureand pressure and can increase or decrease the flow of ablative agent 21through the infusion port 12 to obtain adequate heating or cooling,resulting in adequate ablation. The sensor 17 monitors intraluminalparameters such as temperature and pressure and can increase or decreasethe removal of ablative agent 21 through the optional suction port 13 toobtain adequate heating or cooling resulting in adequate ablation ofBarrett's esophagus 31. FIG. 3B illustrates the ablation device placedin an upper gastrointestinal tract with Barrett's esophagus toselectively ablate the Barrett's tissue, in accordance with anotherembodiment of the present invention. As illustrated in FIG. 3B, thepositioning device 11 is a wire mesh disc. In one embodiment, thepositioning attachment must be separated from the ablation region by adistance of greater than 0 mm, preferably 1 mm and ideally 1 cm. In oneembodiment, the positioning attachment is removably affixed to thecardia or gastroesophageal (EG) junction (for the distal attachment) orin the esophagus by a distance of greater than 0.1 mm, preferably around1 cm, above the proximal most extent of the Barrett's tissue (for theproximal attachment).

FIG. 3B is another embodiment of the Barrett's ablation device where thepositioning element 11 is a wire mesh disc. The wire mesh may have anoptional insulated membrane to prevent the escape of the ablative agent.In the current embodiment, two wire mesh discs are used to center theablation catheter in the esophagus. The distance between the two discsis determined by the length of the tissue to be ablated which, in thiscase, would be the length of the Barrett's esophagus. Optional infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensors18 are incorporated to measure the diameter of the esophagus.

FIG. 3C is a flowchart illustrating the basic procedural steps for usingthe ablation device, in accordance with an embodiment of the presentinvention. At step 302, a catheter of the ablation device is insertedinto an organ which is to be ablated. For example, in order to performablation in a Barrett's esophagus of a patient, the catheter is insertedinto the Barrett's esophagus via the esophagus of the patient.

At step 304, a positioning element of the ablation device is deployedand organ dimensions are measured. In an embodiment, where thepositioning element is a balloon, the balloon is inflated in order toposition the ablation device at a known fixed distance from the tissueto be ablated. In various embodiments, the diameter of the hollow organmay be predetermined by using radiological tests such as barium X-raysor computer tomography (CT) scan, or by using pressure volume cycle,i.e. by determining volume needed to raise pressure to a fixed level(for example, 1 atm) in a fixed volume balloon. In another embodiment,where the positioning device is disc shaped, circumferential rings areprovided in order to visually communicate to an operating physician thediameter of the hollow organ. In various embodiments of the presentinvention, the positioning device enables centering of the catheter ofthe ablation device in a non-cylindrical body cavity, and the volume ofthe cavity is measured by the length of catheter or a uterine sound.

Optionally, one or more infrared, electromagnetic, acoustic orradiofrequency energy emitters and sensors can be used to measure thedimensions of the hollow organ. The infrared, electromagnetic, acousticor radiofrequency energy is emitted from the emitter and is reflectedback from the tissue to a detector in the emitter. The reflected datacan be used to determine the dimensions of the hollow cavity. Themeasurement can be performed at one or multiple points to get anaccurate estimate of the dimensions of the hollow organ. The data frommultiple points can also be used to create a topographic representationof the hollow organ or to calculate the volume of the hollow organ.

In one embodiment, the positioning attachment must be separated from theports by a distance of 0 mm or greater, preferably greater than 0.1 mm,and more preferably 1 cm. The size of the positioning device depends onthe hollow organ being ablated and ranges from 1 mm to 10 cm. In oneembodiment, the diameter of the positioning element is between 0.01 mmand 100 mm. In one embodiment, the first positioning element comprises acircular body with a diameter between 0.01 mm and 10 cm.

At step 306, the organ is ablated by automated delivery of an ablativeagent, such as steam, via infusion ports provided on the catheter. Thedelivery of the ablative agent through the infusion ports is controlledby a microprocessor coupled with the ablation device. The delivery ofablative agent is guided by predetermined programmatic instructionsdepending on the tissue to be ablated and the depth of ablationrequired. In an embodiment of the present invention where the ablativeagent is steam, the dose of the ablative agent is determined byconducting dosimetery study to determine the dose to ablate endometrialtissue. The variable that enables determination of total dose ofablative agent is the volume (or mass) of the tissue to be treated whichis calculated by using the length of the catheter and diameter of theorgan (for cylindrical organs). The determined dose of ablative agent isthen delivered using a micro-processor controlled steam generator.Optionally, the delivery of the ablative agent can be controlled by theoperator using predetermined dosimetry parameters.

In one embodiment, the dose is provided by first determining what thedisorder being treated is and what the desired tissue effect is, andthen finding the corresponding temperature, as shown in Tables 1 and 2,below.

TABLE 1 Temp in ° C. Tissue Effect 37-40 No significant tissue effect41-44 Reversible cell damage in few hours 45-49 Irreversible cell damageat shorter intervals 50-69 Irreversible cell damage -ablation necrosisat shorter intervals  70 Threshold temp for tissue shrinkage, H-bondbreakage 70-99 Coagulation and Hemostasis 100-200 Desiccation andCarbonization of tissue >200 Charring of tissue glucose

TABLE 2 Disorder Max. Temp in ° C. ENT/Pulmonary Nasal Polyp 60-80Turbinectomy 70-85 Bullous Disease 70-85 Lung Reduction 70-85Genitourinary Uterine Menorrhagia 80-90 Endometriosis 80-90 UterineFibroids  90-100 Benign Prostatic Hypertrophy  90-100 GastroenterologyBarrett's Esophagus 60-75 Esophageal Dysplasia 60-80 Vascular GIDisorders 55-75 Flat Polyps 60-80

In addition, the depth of ablation desired determines the holding timeat the maximum temperature. For superficial ablation (Barrett), theholding time at the maximum temperature is very short (flash burn) anddoes not allow for heat to transfer to the deeper layers. This willprevent damage to deeper normal tissue and hence prevent patientdiscomfort and complications. For deeper tissue ablation, the holdingtime at the maximum temperature will be longer, thereby allowing theheat to percolate deeper.

FIG. 4A illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with an embodiment of the presentinvention. The ablation catheter 10 is passed through a colonoscope 40.The positioning device 11 is placed proximal, with respect to thepatient's GI tract, to a flat colonic polyp 41 which is to be ablated,in the normal colon 42. The positioning device 11 is one of aninflatable balloon, a wire mesh disc with or without an insulatedmembrane covering the disc, a cone shaped attachment, a ring shapedattachment or a freeform attachment designed to fit the colonic lumen.The positioning device 11 has the catheter 10 located toward theperiphery of the positioning device 11 placing it closer to the polyp 41targeted for non-circumferential ablation. Hence, the positioning device11 fixes the catheter to the colon 42 at a predetermined distance fromthe polyp 41 for uniform and focused delivery of the ablative agent 21.The delivery of ablative agent 21 through the infusion port 12 iscontrolled by the microprocessor 15 attached to the ablation device anddepends on tissue and the depth of ablation required. The delivery ofablative agent 21 is guided by predetermined programmatic instructionsdepending on the tissue to be ablated and the area and depth of ablationrequired. Optional infrared, electromagnetic, acoustic or radiofrequencyenergy emitters and sensors 18 are incorporated to measure the diameterof the colon. The ablation device allows for focal ablation of diseasedpolyp mucosa without damaging the normal colonic mucosa located awayfrom the catheter ports.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, ideally more than5 mm. In one embodiment, the positioning element is proximal, withrespect to the patient's GI tract, to the colon polyp.

FIG. 4B illustrates the ablation device placed in a colon 42 to ablate aflat colon polyp 41, in accordance with another embodiment of thepresent invention. As illustrated in FIG. 4B, the positioning device 11is a conical attachment at the tip of the catheter 10. The conicalattachment has a known length ‘l’ and diameter ‘d’ that is used tocalculate the amount of thermal energy needed to ablate the flat colonpolyp 41. Ablative agent 21 is directed from the infusion port 12 topolyp 41 by the positioning device 11. In one embodiment, thepositioning attachment 11 must be separated from the ablation region bya distance of greater than 0.1 mm, preferably 1 mm and more preferably 1cm. In one embodiment, the length ‘l’ is greater than 0.1 mm, preferablybetween 5 and 10 mm. In one embodiment, diameter ‘d’ depends on the sizeof the polyp and can be between 1 mm and 10 cm, preferably 1 to 5 cm.Optional infrared, electromagnetic, acoustic or radiofrequency energyemitters and sensors 18 are incorporated to measure the diameter of thecolon. This embodiment can also be used to ablate residual neoplastictissue at the edges after endoscopic snare resection of a large sessilecolon polyp.

FIG. 5A illustrates the ablation device with a coaxial catheter design,in accordance with an embodiment of the present invention. The coaxialdesign has a handle 52 a, an infusion port 53 a, an inner sheath 54 aand an outer sheath 55 a. The outer sheath 55 a is used to constrain thepositioning device 56 a in the closed position and encompasses ports 57a. FIG. 5B shows a partially deployed positioning device 56 b, with theports 57 b still within the outer sheath 55 b. The positioning device 56b is partially deployed by pushing the catheter 54 b out of sheath 55 b.

FIG. 5C shows a completely deployed positioning device 56 c. Theinfusion ports 57 c are out of the sheath 55 c. The length ‘l’ of thecatheter 54 c that contains the infusion ports 57 c and the diameter ‘d’of the positioning element 56 c are predetermined/known and are used tocalculate the amount of thermal energy needed. FIG. 5D illustrates aconical design of the positioning element. The positioning element 56 dis conical with a known length ‘l’ and diameter ‘d’ that is used tocalculate the amount of thermal energy needed for ablation. FIG. 5Eillustrates a disc shaped design of the positioning element 56 ecomprising circumferential rings 59 e. The circumferential rings 59 eare provided at a fixed predetermined distance from the catheter 54 eand are used to estimate the diameter of a hollow organ or hollowpassage in a patient's body.

FIG. 6 illustrates an upper gastrointestinal tract with a bleedingvascular lesion being treated by the ablation device, in accordance withan embodiment of the present invention. The vascular lesion is a visiblevessel 61 in the base of an ulcer 62. The ablation catheter 63 is passedthrough the channel of an endoscope 64. The conical positioning element65 is placed over the visible vessel 61. The conical positioning element65 has a known length ‘l’ and diameter ‘d’, which are used to calculatethe amount of thermal energy needed for coagulation of the visiblevessel to achieve hemostasis. The conical positioning element has anoptional insulated membrane that prevents escape of thermal energy orvapor away from the disease site.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In one embodiment, the length ‘l’ is greaterthan 0.1 mm, preferably between 5 and 10 mm. In one embodiment, diameter‘d’ depends on the size of the lesion and can be between 1 mm and 10 cm,preferably 1 to 5 cm.

FIG. 7 illustrates endometrial ablation being performed in a femaleuterus by using the ablation device, in accordance with an embodiment ofthe present invention. A cross-section of the female genital tractcomprising a vagina 70, a cervix 71, a uterus 72, an endometrium 73,fallopian tubes 74, ovaries 75 and the fundus of the uterus 76 isillustrated. A catheter 77 of the ablation device is inserted into theuterus 72 through the cervix 71. In an embodiment, the catheter 77 hastwo positioning elements, a conical positioning element 78 and a discshaped positioning element 79. The positioning element 78 is conicalwith an insulated membrane covering the conical positioning element 78.The conical element 78 positions the catheter 77 in the center of thecervix 71 and the insulated membrane prevents the escape of thermalenergy or ablative agent through the cervix 71. The second disc shapedpositioning element 79 is deployed close to the fundus of the uterus 76positioning the catheter 77 in the middle of the cavity. An ablativeagent 778 is passed through infusion ports 777 for uniform delivery ofthe ablative agent 778 into the uterine cavity. Predetermined length “l”of the ablative segment of the catheter and diameter ‘d’ of thepositioning element 79 allows for estimation of the cavity size and isused to calculate the amount of thermal energy needed to ablate theendometrial lining. Optional temperature sensors 7 deployed close to theendometrial surface are used to control the delivery of the ablativeagent 778. Optional topographic mapping using multiple infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensorscan be used to define cavity size and shape in patients with anirregular or deformed uterine cavity due to conditions such as fibroids.Additionally data from diagnostic testing can be used to ascertain theuterine cavity size, shape or other characteristics.

In an embodiment, the ablative agent is vapor or steam which contractson cooling. Steam turns to water which has a lower volume as compared toa cryogen that will expand or a hot fluid used in hydrothermal ablationwhose volume stays constant. With both cryogens and hot fluids,increasing energy delivery is associated with increasing volume of theablative agent which, in turn, requires mechanisms for removing theagent, otherwise the medical provider will run into complications, suchas perforation. However, steam, on cooling, turns into water whichoccupies significantly less volume; therefore, increasing energydelivery is not associated with an increase in volume of the residualablative agent, thereby eliminating the need for continued removal. Thisfurther decreases the risk of leakage of the thermal energy via thefallopian tubes 74 or the cervix 71, thus reducing any risk of thermalinjury to adjacent healthy tissue.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In another embodiment, the positioningattachment can be in the ablated region as long as it does not cover asignificant surface area. For endometrial ablation, 100% of the tissuedoes not need to be ablated to achieve the desired therapeutic effect.

In one embodiment, the preferred distal positioning attachment is anuncovered wire mesh that is positioned proximate to the mid body region.In one embodiment, the preferred proximal positioning device is acovered wire mesh that is pulled into the cervix, centers the device,and occludes the cervix. One or more such positioning devices may behelpful to compensate for the anatomical variations in the uterus. Theproximal positioning device is preferably oval, with a long axis between0.1 mm and 10 cm (preferably 1 cm to 5 cm) and a short axis between 0.1mm and 5 cm (preferably 0.5 cm to 1 cm). The distal positioning deviceis preferably circular with a diameter between 0.1 mm and 10 cm,preferably 1 cm to 5 cm.

FIG. 8 illustrates sinus ablation being performed in a nasal passage byusing the ablation device, in accordance with an embodiment of thepresent invention. A cross-section of the nasal passage and sinusescomprising nares 81, nasal passages 82, frontal sinus 83, ethmoid sinus84, and diseased sinus epithelium 85 is illustrated. The catheter 86 isinserted into the frontal sinus 83 or the ethmoid sinus 84 through thenares 81 and nasal passages 82.

In an embodiment, the catheter 86 has two positioning elements, aconical positioning element 87 and a disc shaped positioning element 88.The positioning element 87 is conical and has an insulated membranecovering. The conical element 87 positions the catheter 86 in the centerof the sinus opening 80 and the insulated membrane prevents the escapeof thermal energy or ablative agent through the opening. The second discshaped positioning element 88 is deployed in the frontal sinus cavity 83or ethmoid sinus cavity 84, positioning the catheter 86 in the middle ofeither sinus cavity. The ablative agent 8 is passed through the infusionport 89 for uniform delivery of the ablative agent 8 into the sinuscavity. The predetermined length “l” of the ablative segment of thecatheter and diameter of the positioning element 88 allows forestimation of the sinus cavity size and is used to calculate the amountof thermal energy needed to ablate the diseased sinus epithelium 85.Optional temperature sensors 888 are deployed close to the diseasedsinus epithelium 85 to control the delivery of the ablative agent 8. Inan embodiment, the ablative agent 8 is steam which contracts on cooling.This further decreases the risk of leakage of the thermal energy thusreducing any risk of thermal injury to adjacent healthy tissue. In oneembodiment, the dimensional ranges of the positioning elements aresimilar to those in the endometrial application, with preferred maximumranges being half thereof. Optional topographic mapping using multipleinfrared, electromagnetic, acoustic or radiofrequency energy emittersand sensors can be used to define cavity size and shape in patients withan irregular or deformed nasal cavity due to conditions such as nasalpolyps.

FIG. 9 illustrates bronchial and bullous ablation being performed in apulmonary system by using the ablation device, in accordance with anembodiment of the present invention. A cross-section of the pulmonarysystem comprising bronchus 91, normal alveolus 92, bullous lesion 93,and a bronchial neoplasm 94 is illustrated.

In one embodiment, the catheter 96 is inserted through the channel of abronchoscope 95 into the bronchus 91 and advanced into a bullous lesion93. The catheter 96 has two positioning elements, a conical positioningelement 97 and a disc shaped positioning element 98. The positioningelement 97 is conical having an insulated membrane covering. The conicalelement 97 positions the catheter 96 in the center of the bronchus 91and the insulated membrane prevents the escape of thermal energy orablative agent through the opening into the normal bronchus. The seconddisc shaped positioning element 98 is deployed in the bullous cavity 93positioning the catheter 96 in the middle of the bullous cavity 93. Anablative agent 9 is passed through the infusion port 99 for uniformdelivery into the sinus cavity. Predetermined length “l” of the ablativesegment of the catheter 96 and diameter of the positioning element 98allow for estimation of the bullous cavity size and is used to calculatethe amount of thermal energy needed to ablate the diseased bullouscavity 93. Optionally, the size of the cavity can be calculated fromradiological evaluation using a chest CAT scan or MRI. Optionaltemperature sensors are deployed close to the surface of the bullouscavity 93 to control the delivery of the ablative agent 9. In anembodiment, the ablative agent is steam which contracts on cooling. Thisfurther decreases the risk of leakage of the thermal energy into thenormal bronchus thus reducing any risk of thermal injury to adjacentnormal tissue.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In another embodiment, the positioningattachment can be in the ablated region as long as it does not cover asignificant surface area.

In one embodiment, there are preferably two positioning attachments. Inanother embodiment, the endoscope is used as one fixation point with onepositioning element. The positioning device is between 0.1 mm and 5 cm(preferably 1 mm to 2 cm). The distal positioning device is preferablycircular with a diameter between 0.1 mm and 10 cm, preferably 1 cm to 5cm.

In another embodiment for the ablation of a bronchial neoplasm 94, thecatheter 96 is inserted through the channel of a bronchoscope 95 intothe bronchus 91 and advanced across the bronchial neoplasm 94. Thepositioning element 98 is disc shaped having an insulated membranecovering. The positioning element 98 positions the catheter in thecenter of the bronchus 91 and the insulated membrane prevents the escapeof thermal energy or ablative agent through the opening into the normalbronchus. The ablative agent 9 is passed through the infusion port 99 ina non-circumferential pattern for uniform delivery of the ablative agentto the bronchial neoplasm 94. The predetermined length “l” of theablative segment of the catheter and diameter ‘d’ of the positioningelement 98 are used to calculate the amount of thermal energy needed toablate the bronchial neoplasm 94.

The catheter could be advanced to the desired location of ablation usingendoscopic, laparoscopic, stereotactic or radiological guidance.Optionally the catheter could be advanced to the desired location usingmagnetic navigation.

FIG. 10 illustrates prostate ablation being performed on an enlargedprostrate in a male urinary system by using the device, in accordancewith an embodiment of the present invention. A cross-section of a malegenitourinary tract having an enlarged prostate 1001, bladder 1002, andurethra 1003 is illustrated. The urethra 1003 is compressed by theenlarged prostate 1001. The ablation catheter 1005 is passed through thecystoscope 1004 positioned in the urethra 1003 distal to theobstruction. The positioning elements 1006 are deployed to center thecatheter in the urethra 1003 and one or more insulated needles 1007 arepassed to pierce the prostate 1001. The vapor ablative agent 1008 ispassed through the insulated needles 1007 thus causing ablation of thediseased prostatic tissue resulting in shrinkage of the prostate.

The size of the enlarged prostate could be calculated by using thedifferential between the extra-prostatic and intra-prostatic urethra.Normative values could be used as baseline. Additional ports forinfusion of a cooling fluid into the urethra can be provided to preventdamage to the urethra while the ablative energy is being delivered tothe prostrate for ablation, thus preventing complications such asstricture formation.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mm to5 mm and no more than 2 cm. In another embodiment, the positioningattachment can be deployed in the bladder and pulled back into theurethral opening/neck of the bladder thus fixing the catheter. In oneembodiment, the positioning device is between 0.1 mm and 10 cm indiameter.

FIG. 11 illustrates fibroid ablation being performed in a female uterusby using the ablation device, in accordance with an embodiment of thepresent invention. A cross-section of a female genitourinary tractcomprising a uterine fibroid 1111, uterus 1112, and cervix 1113 isillustrated. The ablation catheter 1115 is passed through thehysteroscope 1114 positioned in the uterus distal to the fibroid 1111.The ablation catheter 1115 has a puncturing tip 1120 that helps punctureinto the fibroid 1111. The positioning elements 1116 are deployed tocenter the catheter in the fibroid and insulated needles 1117 are passedto pierce the fibroid tissue 1111. The vapor ablative agent 1118 ispassed through the needles 1117 thus causing ablation of the uterinefibroid 1111 resulting in shrinkage of the fibroid.

FIG. 12 illustrates a vapor delivery system using an RF heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention. In an embodiment, the vapor is used as anablative agent in conjunction with the ablation device described in thepresent invention. RF heater 1264 is located proximate a pressure vessel1242 containing a liquid 1244. RF heater 1264 heats vessel 1242, in turnheating the liquid 1244. The liquid 1244 heats up and begins toevaporate causing an increase in pressure inside the vessel 1242. Thepressure inside vessel 1242 can be kept fairly constant by providing athermal switch 1246 that controls resistive heater 1264. Once thetemperature of the liquid 1244 reaches a predetermined temperature, thethermal switch 1246 shuts off RF heater 1264. The vapor created inpressure vessel 1242 may be released via a control valve 1250. As thevapor exits vessel 1242, a pressure drop is created in the vesselresulting in a reduction in temperature. The reduction of temperature ismeasured by thermal switch 1246, and RF heater 1264 is turned back on toheat liquid 1244. In one embodiment, the target temperature of vessel1242 may be set to approximately 108° C., providing a continuous supplyof vapor. As the vapor is released, it undergoes a pressure drop, whichreduces the temperature of the vapor to a range of approximately 90-100°C. As liquid 1244 in vessel 1242 evaporates and the vapor exits vessel1242, the amount of liquid 1244 slowly diminishes. The vessel 1242 isoptionally connected to reservoir 1243 containing liquid 1244 via a pump1249 which can be turned on by the controller 1224 upon sensing a fallin pressure or temperature in vessel 1242, delivering additional liquid1244 to the vessel 1242.

Vapor delivery catheter 1216 is connected to vessel 1242 via a fluidconnector 1256. When control valve 1250 is open, vessel 1242 is in fluidcommunication with delivery catheter 1216 via connector 1256. Controlswitch 1260 may serve to turn vapor delivery on and off via actuator1248. For example, control switch 1260 may physically open and close thevalve 1250, via actuator 1248, to control delivery of vapor stream fromthe vessel 1242. Switch 1260 may be configured to control otherattributes of the vapor such as direction, flow, pressure, volume, spraydiameter, or other parameters.

Instead of, or in addition to, physically controlling attributes of thevapor, switch 1260 may electrically communicate with a controller 1224.Controller 1224 controls the RF heater 1264, which in turn controlsattributes of the vapor, in response to actuation of switch 1260 by theoperator. In addition, controller 1224 may control valves temperature orpressure regulators associated with catheter 1216 or vessel 1242. A flowmeter 1252 may be used to measure the flow, pressure, or volume of vapordelivery via the catheter 1216. The controller 1224 controls thetemperature and pressure in the vessel 1242 and the time, rate, flow,and volume of vapor flow through the control valve 1250. Theseparameters are set by the operator 1211. The pressure created in vessel1242, using the target temperature of 108° C., may be in the order of 25pounds per square inch (psi) (1.72 bars).

FIG. 13 illustrates a vapor delivery system using a resistive heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention. In an embodiment, the generated vapor is usedas an ablative agent in conjunction with the ablation device describedin the present invention. Resistive heater 1340 is located proximate apressure vessel 1342. Vessel 1342 contains a liquid 1344. Resistiveheater 1340 heats vessel 1342, in turn heating liquid 1344. Accordingly,liquid 1344 heats and begins to evaporate. As liquid 1344 begins toevaporate, the vapor inside vessel 1342 causes an increase in pressurein the vessel. The pressure in vessel 1342 can be kept fairly constantby providing a thermal switch 1346 that controls resistive heater 1340.When the temperature of liquid 1344 reaches a predetermined temperature,thermal switch 1346 shuts off resistive heater 1340. The vapor createdin pressure vessel 1342 may be released via a control valve 1350. As thevapor exits vessel 1342, vessel 1342 experiences a pressure drop. Thepressure drop of vessel 1342 results in a reduction of temperature. Thereduction of temperature is measured by thermal switch 1346, andresistive heater 1340 is turned back on to heat liquid 1344. In oneembodiment, the target temperature of vessel 1342 may be set toapproximately 108° C., providing a continuous supply of vapor. As thevapor is released, it undergoes a pressure drop, which reduces thetemperature of the vapor to a range of approximately 90-100° C. Asliquid 1344 in vessel 1342 evaporates and the vapor exits vessel 1342,the amount of liquid 1344 slowly diminishes. The vessel 1342 isconnected to another vessel 1343 containing liquid 1344 via a pump 1349which can be turned on by the controller 1324 upon sensing a fall inpressure or temperature in vessel 1342 delivering additional liquid 1344to the vessel 1342.

Vapor delivery catheter 1316 is connected to vessel 1342 via a fluidconnector 1356. When control valve 1350 is open, vessel 1342 is in fluidcommunication with delivery catheter 1316 via connector 1356. Controlswitch 1360 may serve to turn vapor delivery on and off via actuator1348. For example, control switch 1360 may physically open and close thevalve 1350, via actuator 1348, to control delivery of vapor stream fromthe vessel 1342. Switch 1360 may be configured to control otherattributes of the vapor such as direction, flow, pressure, volume, spraydiameter, or other parameters. Instead of, or in addition to, physicallycontrolling attributes of the vapor, switch 1360 may electricallycommunicate with a controller 1324. Controller 1324 controls theresistive heater 1340, which in turn controls attributes of the vapor,in response to actuation of switch 1360 by the operator. In addition,controller 1324 may control valves temperature or pressure regulatorsassociated with catheter 1316 or vessel 1342. A flow meter 1352 may beused to measure the flow, pressure, or volume of vapor delivery via thecatheter 1316. The controller 1324 controls the temperature and pressurein the vessel 1342 as well as time, rate, flow, and volume of vapor flowthrough the control valve 1350. These parameters are set by the operator1311. The pressure created in vessel 1342, using the target temperatureof 108° C., may be on the order of 25 pounds per square inch (psi) (1.72bars).

FIG. 14 illustrates a vapor delivery system using a heating coil forsupplying vapor to the ablation device, in accordance with an embodimentof the present invention. In an embodiment, the generated vapor is usedas an ablative agent in conjunction with the ablation device describedin the present invention. The vapor delivery system includes aconventional generator 1400 that is commonly used in operating rooms toprovide power to specialized tools, i.e., cutters. The generator 1400 ismodified to include an integrated liquid reservoir 1401. In oneembodiment, the reservoir 1401 is filled with room temperature purewater. The reservoir 1401 portion of the generator 1400 is connected tothe heating component 1405 via a reusable active cord 1403. In oneembodiment, the reusable active cord 1403 may be used up to 200 times.The cord 1403 is fixedly attached via connections at both ends towithstand operational pressures, and preferably a maximum pressure, suchthat the cord does not become disconnected. In one embodiment, theconnections can resist at least 1 atm of pressure. In one embodiment,the connections are of a luer lock type. The cord 1403 has a lumenthrough which liquid flows to the heating component 1405. In oneembodiment, the heating component 1405 contains a coiled length oftubing 1406. As liquid flows through the coiled tubing 1406, it isheated by the surrounding heating component 1405 in a fashion similar toa conventional heat exchanger. As the liquid is heated, it becomesvaporized. The heating component contains a connector 1407 thataccommodates the outlet of vapor from the coiled tubing 1406. One end ofa single use cord 1408 attaches to the heating component 1405 at theconnector 1407. The connector 1407 is designed to withstand pressuresgenerated by the vapor inside the coiled tubing 1406 during operation.In one embodiment, the connector 1407 is of a luer lock type. Anablation device 1409 is attached to the other end of the single use cord1408 via a connection able to withstand the pressures generated by thesystem. In one embodiment, the ablation device is integrated with acatheter. In another embodiment, the ablation device is integrated witha probe. The single use cord 1408 has a specific luminal diameter and isof a specific length to ensure that the contained vapor does notcondense into liquid while simultaneously providing the user enoughslack to operate. In addition, the single use cord 1408 providessufficient insulation so that personnel will not suffer burns whencoming into contact with the cord. In one embodiment, the single usecord has a luminal diameter of less than 3 mm, preferably less than 2.6mm, and is longer than 1 meter in length.

In one embodiment, the system includes a foot pedal 1402 by which theuser can supply more vapor to the ablation device. Depressing the footpedal 1402 allows liquid to flow from the reservoir 1401 into theheating component 1405 where it changes into vapor within the coiledtubing 1406. The vapor then flows to the ablation device via the singleuse tube 1408. The ablation device includes an actuator by which theuser can open small ports on the device, releasing the vapor andablating the target tissue.

FIG. 15 illustrates the heating component 1505 and coiled tubing 1506 ofthe heating coil vapor delivery system of FIG. 14, in accordance with anembodiment of the present invention. Liquid arrives through a reusableactive cord (not shown) at a connection 1502 on one side of the heatingcomponent 1505. The liquid then travels through the coiled tubing 1506within the heating component 1505. The coiled tubing is composed of amaterial and configured specifically to provide optimal heat transfer tothe liquid. In one embodiment, the coiled tubing 1506 is copper. Thetemperature of the heating component 1505 is set to a range so that theliquid is converted to vapor as it passes through the coiled tubing1506. In one embodiment, the temperature of the heating component 1505can be set by the user through the use of a temperature setting dial1508. In one embodiment, the heating component contains an on/off switch1509 and is powered through the use of an attached AC power cord 1503.In another embodiment, the heating component receives power through anelectrical connection integrated into and/or facilitated by the activecord connection to the reservoir. The vapor passes through the end ofthe coiled tubing 1506 and out of the heating component 1505 through aconnector 1507. In one embodiment, the connector 1507 is located on theopposite side of the heating component 1505 from the inlet connection1502. A single use cord (not shown) attaches to the connector 1507 andsupplies vapor to the ablation device.

FIG. 16A illustrates the unassembled interface connection between theablation device 1608 and the single use cord 1601 of the heating coilvapor delivery system of FIG. 14, in accordance with an embodiment ofthe present invention. In this embodiment, the ablation device 1608 andsingle use cord 1601 are connected via a male-to-male double luer lockadapter 1605. The end of the single use cord 1601 is threaded to form afemale end 1602 of a luer lock interface and connects to one end of theadapter 1605. The ablation device 1608 includes a small protrusion atits non-operational end which is also threaded to form a female end 1607of a luer lock interface and connects to the other end of the adapter1605. The threading luer lock interface provides a secure connection andis able to withstand the pressures generated by the heating coil vapordelivery system without becoming disconnected.

FIG. 16B illustrates the assembled interface connection between theablation device 1608 and the single use cord 1601 of the heating coilvapor delivery system of FIG. 14, in accordance with an embodiment ofthe present invention. The male-to-male double luer lock adapter 1605 ispictured securing the two components together. The double luer lockinterface provides a stable seal, allows interchangeability betweenablation devices, and enables users to quickly replace single use cords.

FIG. 17 illustrates a vapor ablation system using a heater or heatexchange unit for supplying vapor to the ablation device, in accordancewith another embodiment of the present invention. In the picturedembodiment, water for conversion to vapor is supplied in a disposable,single use sterile fluid container 1705. The container 1705 is sealedwith a sterile screw top 1710 that is punctured by a needle connector1715 provided on a first end of a first filter member 1720. The secondend of the first filter member 1720, opposite the first end, isconnected to a pump 1725 for drawing the water from the fluid container1705, through the first filter member 1720, and into the heater or heatexchange unit 1730. The system includes a microcontroller ormicroprocessor 1735 for controlling the actions of the pump 1725 andheater or heat exchange unit 1730. The heater or heat exchange unit 1730converts the water into vapor (steam). The increase in pressuregenerated during the heating step drives the vapor through an optionalsecond filter member 1740 and into the ablation catheter 1750. In oneembodiment, the heater or heat exchange unit 1730 includes a one-wayvalve at its proximal end to prevent the passage of vapor back towardthe pump 1725. In various embodiments, optional sensors 1745 positionedproximate the distal end of the catheter 1750 measure one or more oftemperature, pressure, or flow of vapor and transmit the information tothe microcontroller 1735, which in turn controls the rate of the pump1725 and the level of vaporizing energy provided by the heater or heatexchange unit 1730.

FIG. 18 illustrates the fluid container 1805, first filter member 1820,and pump 1825 of the vapor ablation system of FIG. 17. As can be seen inthe pictured embodiment, the system includes a water-filled, disposable,single use sterile fluid container 1805 and a pump 1825 with a firstfilter member 1820 disposed therebetween. The first filter member 1820is connected to the container 1805 and pump 1825 by two first and secondlengths of sterile tubing 1807, 1822 respectively, and includes a filterfor purifying the water used in the ablation system.

FIGS. 19 and 20 illustrate first and second views respectively, of thefluid container 1905, 2005, first filter member 1920, 2020, pump 1925,2025, heater or heat exchange unit 1930, 2030, and microcontroller 1935,2035 of the vapor ablation system of FIG. 17. The container 1905, 2005is connected to the first filter member 1920, 2020 by a first length ofsterile tubing 1907, 2007 and the first filter member 1920, 2020 isconnected to the pump 1925, 2025 by a second length of sterile tubing1922, 2022. A third length of sterile tubing 1927, 2027 connects thepump 1925, 2025 to the heater or heat exchange unit 1930, 2030. Themicrocontroller 1935, 2035, is operably connected to the pump 1925, 2025by a first set of control wires 1928, 2028 and to the heater or heatexchange unit 1930, 2030 by a second set of control wires 1929, 2029.The arrows 1901, 2001 depict the direction of the flow of water from thecontainer 1905, 2005, through the first filter member 1920, 2020 andpump 1925, 2025 and into the heater or heat exchange member 1930, 2030where it is converted to vapor. Arrow 1931, 2031 depicts the directionof flow of vapor from the heater or heat exchange unit 1930, 2030 intothe ablation catheter (not shown) for use in the ablation procedure.

FIG. 21 illustrates the unassembled first filter member 2120 of thevapor ablation system of FIG. 17, depicting the filter 2122 positionedwithin. In one embodiment, the first filter member 2120 includes aproximal portion 2121, a distal portion 2123, and a filter 2122. Theproximal portion 2121 and distal portion 2123 secure together and holdthe filter 2122 within. Also depicted in FIG. 21 are the disposable,single use sterile fluid container 2105 and the first length of steriletubing 2107 connecting the container 2105 to the proximal portion 2121of the first filter member 2120.

FIG. 22 illustrates one embodiment of the microcontroller 2200 of thevapor ablation system of FIG. 17. In various embodiments, themicrocontroller 2200 includes a plurality of control wires 2228connected to the pump and heater or heat exchange unit for controllingsaid components and a plurality of transmission wires 2247 for receivingflow, pressure, and temperature information from optional sensorspositioned proximate the distal end of the ablation catheter.

FIG. 23 illustrates one embodiment of a catheter assembly 2350 for usewith the vapor ablation system of FIG. 17. Vapor is delivered from theheater or heat exchange unit to the catheter assembly 2350 via a tube2348 attached to the proximal end of a connector component 2352 of theassembly 2350. A disposable catheter 2356 with a fixedly attacheddisposable length of flexible tubing 2358 at its distal end is fittedover the connector component 2352. A second filter member 2354 ispositioned between the connector component 2352 and the disposablecatheter 2356 for purifying the vapor supplied by the heater or heatexchange unit. The connector component 2352 includes two washers 2353positioned apart a short distance at its distal end to engage theoverlaying disposable catheter 2356 and form a double-stage seal,thereby preventing vapor leakage between the components. Once thedisposable catheter 2356 has been fitted to the distal end of theconnector component 2352, a catheter connector 2357 is slid over thedisposable flexible tubing 2358 and disposable catheter 2356 and is thensnapped into place onto the connector component 2352. The catheterconnector 2357 acts to keep the disposable catheter 2356 in place andalso assists in preventing vapor leakage. In various embodiments, thedisposable flexible tubing 2358 includes one or more holes or ports 2359at or proximate its distal end for the delivery of ablative vapor totarget tissues.

FIG. 24 illustrates one embodiment of a heat exchange unit 2430 for usewith the vapor ablation system of FIG. 17. The heat exchange unit 2430comprises a length of coiled tubing 2435 surrounded by a heating element2434. Water 2432 enters the coiled tubing 2435 of the heat exchange unit2430 at an entrance port 2433 proximate a first end of said heatexchange unit 2430. As the water 2432 flows within the coiled tubing2435, it is converted into vapor (steam) 2438 by the heat emanating fromsaid coiled tubing 2435 which has been heated by the heating element2434. The vapor 2438 exits the coiled tubing 2435 of the heat exchangeunit 2430 at an exit port 2437 proximate a second end of said heatexchange unit 2430 and is then delivered to the ablation catheter (notshown) for use in the ablation procedure.

FIG. 25 illustrates another embodiment of a heat exchange unit 2560 foruse with the vapor ablation system of the present invention. In thepictured embodiment, the heat exchange unit 2560 comprises acylindrically shaped, pen sized ‘clamshell’ style heating block. Theheating block of the heat exchange unit 2560 includes a first half 2561and a second half 2562 fixedly attached by a hinge 2563 along one side,wherein the halves 2561, 2562 fold together and connect on the oppositeside. In one embodiment, the sides of the halves opposite sides with thehinge include a clasp for holding the two halves together. In oneembodiment, one of the halves includes a handle 2564 for manipulatingthe heat exchange unit 2560. When the halves are folded together, theheat exchange unit 2560 snugly envelopes a cylindrically shaped catheterfluid heating chamber 2551 attached to, in-line and in fluidcommunication with, the proximal end of the ablation catheter 2550. Eachhalf 2561, 2562 of the heat exchange unit 2560 includes a plurality ofheating elements 2565 for heating the block. The positioning and fit ofthe heating block place it in close thermal contact with the catheterfluid heating chamber 2551. When in operation, the heating elements 2565heat the heating block which transfers heat to the catheter fluidheating chamber 2551, which in turn heats the water inside the chamber2551, converting said water to vapor. The heating block does notdirectly contact the water. In one embodiment, the catheter fluidheating chamber 2551 comprises a plurality of linear indentations 2591stretching along the length of the component and in parallel with theheating elements 2565. Upon closing the halves 2561, 2562, the heatingelements 2565, which optionally protrude from the internal surfaces ofthe halves 2561, 2562 contact, and fit within, the linear indentations2591. This also increases the surface area of contact between theheating block and the heating chamber, improving the efficiency of heatexchange.

A luer fitting coupler 2549 is provided at the proximal end of thecatheter fluid heating chamber 2551 for connecting a tube supplyingsterile water. In one embodiment, a one-way valve is included at theproximal end of the catheter fluid heating chamber 2551, distal to theluer fitting 2549, to prevent the passage of vapor under pressure towardthe water supply.

As described above, the catheter fluid heating chamber is designed aspart of the ablation catheter and, along with the remainder of thecatheter, is single use and disposable. In another embodiment, thechamber is reusable, in which case the luer fitting is positioned inbetween the catheter shaft and the chamber. The heating block isdesigned to be axially aligned with the heating chamber when in use, isreusable, and will not be damaged in the event that it falls to thefloor. In one embodiment, the weight and dimensions of the heating blockare designed such that it can be integrated into a pen-sized and shapedhandle of the ablation catheter. The handle is thermally insulated toprevent injury to the operator.

In one embodiment, the heating block receives its power from a consolewhich is itself line powered and designed to provide 700-1000 W ofpower, as determined by the fluid vaporization rate. The heating blockand all output connections are electrically isolated from line voltage.In one embodiment, the console includes a user interface allowingadjustment of power with a commensurate fluid flow rate. In addition, inone embodiment, a pump, such as a syringe pump, is used to control theflow of fluid to the heating chamber and heating element. In oneembodiment, the volume of the syringe is at least 10 ml and is ideally60 ml.

In the above embodiment, the catheter to be used with the vapor ablationsystem is designed using materials intended to minimize cost. In oneembodiment, the tubing used with the catheter is able to withstand atemperature of at least 125° C. and can flex through an endoscope's bendradius (approximately 1 inch) without collapse. In one embodiment, thesection of the catheter that passes through an endoscope is 7 French(2.3 mm) diameter and has a minimum length of 215 cm. In one embodiment,thermal resistance is provided by the catheter shaft material whichshields the endoscope from the super-heated vapor temperature. In oneembodiment, the heat exchange unit is designed to interface directlywith, or in very close proximity to, an endoscope's biopsy channel tominimize the likelihood of a physician handling heated components.Having the heat exchange unit in close proximity to the endoscope handlealso minimizes the length of the catheter through which the vapor needsto travel, thus minimizing heat loss and premature condensation.

In various embodiments, other means are used to heat the fluid withinthe catheter fluid heating chamber. FIG. 26 illustrates the use ofinduction heating to heat a chamber 2605. When an alternating electriccurrent is passed through a coil of wire within the chamber 2605, thecoil creates a magnetic field. The magnetic lines of flux 2610 cutthrough the air around the coil. When the chamber 2605 is composed of aferrous material, such as, iron, stainless steel, or copper, electricalcurrents known as eddy currents are induced to flow in the chamber 2605,resulting in localized heating of the chamber 2605.

FIG. 27A illustrates one embodiment of a coil 2770 used with inductionheating in the vapor ablation system of the present invention. The coilis positioned surrounding the catheter fluid heating chamber 2751. Analternating current passing through the coil creates a magnetic fieldand results in heating of the catheter fluid heating chamber 2751. Theheated chamber heats the fluid within, converting it into a vapor, whichpasses into the catheter 2750 for use in the ablation procedure. Thecoil itself does not heat, making it safe to touch. A luer fittingcoupler 2749 is provided at the proximal end of the catheter fluidheating chamber 2751 for connecting a tube supplying sterile water. Inone embodiment, a one-way valve (not shown) is included at the proximalend of the catheter fluid heating chamber 2751, distal to the luerfitting 2749, to prevent the passage of vapor toward the water supply.In one embodiment, thermal insulating material (not shown) is positionedbetween the coil 2770 and the heating chamber 2751. In anotherembodiment, the chamber 2751 is suspended in the center of the coil 2770with no physical contact between the two. In this embodiment, theintervening air acts as a thermally insulating material. The design ofthe chamber is optimized to increase its surface area to maximizecontact and heat transfer, in turn resulting in more efficient vaporgeneration.

FIG. 27B illustrates one embodiment of a catheter handle 2772 used withinduction heating in the vapor ablation system of the present invention.The handle 2772 is thermally insulated and incorporates an inductioncoil. In one embodiment, the handle 2772 includes an insulated tip 2773at its distal end that engages with an endoscope channel after thecatheter is inserted into the endoscope. The catheter 2750 is connectedto the heating chamber 2751 which in turn is connected with the pump viaan insulated connector 2774. In one embodiment, the heating chamber 2751length and diameter are less than those of the handle 2772 and theinduction coil, thus the heating chamber 2751 can slide inside thehandle 2772 in a coaxial fashion while maintaining a constant positionwithin the magnetic field generated by the induction coil. The operatorcan manipulate the catheter 2750 by grasping on the insulated connector2774 and moving it in and out of the handle 2772 which in turn moves thecatheter tip in and out of the distal end of the endoscope. In thisdesign, the heated portions of the catheter 2750 are within the channelof the endoscope and in the insulated handle 2772, thus not coming intocontact with the operator at anytime during the operation. An optionalsensor 2775 on the insulated tip 2773 can sense when the catheter is notengaged with the endoscope and temporarily disable the heating functionof the catheter to prevent accidental activation and thermal injury tothe operator. With respect to FIG. 27B, the catheter 2750 and heatingchamber 2751 are the heated components of the system while the handle2772, insulated tip 2773, and insulated connector 2774 are the coolcomponents and therefore safe to touch by the user.

FIGS. 28A and 28B are front and longitudinal view cross sectionaldiagrams respectively, illustrating one embodiment of a catheter 2880used with induction heating in the vapor ablation system of the presentinvention. The catheter 2880 includes an insulated handle 2886 thatcontains a heating chamber 2851 and an induction coil 2884. The heatingchamber 2851 includes a luer lock 2849 at its proximal end. The luerlock 2849 has a one-way valve that prevents the backward flow of vaporfrom the chamber 2851. Vaporization of fluid in the chamber results involume expansion and an increase in pressure which pushes the vapor outof the chamber 2849 and into the catheter body. The induction coil 2884includes a wire 2886 that extends from the proximal end of the catheter2880 for the delivery of an alternating current. The handle 2886 isconnected to the catheter 2880 with an outer insulating sheath 2881 madeof a thermally insulating material.

In various embodiments, the insulating material is polyether etherketone (PEEK), polytetrafluoroethylene (PTFE), fluorinated ethylenepropylene (FEP), polyether block amide (PEBA), polyimide, or a similarmaterial. In various embodiments, optional sensors 2887 positionedproximate the distal end of the catheter 2880 measure one or more oftemperature, pressure, or flow of vapor and transmit the information toa microprocessor, which in turn controls the flow rate of the fluid andthe level of vaporizing energy provided to the chamber 2851. Themicrocontroller adjusts fluid flow rate and chamber temperature based onthe sensed information, thereby controlling the flow of vapor and inturn, the flow of ablative energy to the target tissue.

In one embodiment, the catheter 2880 includes an inner flexible metalskeleton 2883. In various embodiments, the skeleton 2883 is composed ofcopper, stainless steel, or another ferric material. The skeleton 2883is in thermal contact with the heating chamber 2851 so that the heatfrom the chamber 2851 is passively conducted through the metal skeleton2883 to heat the inside of the catheter 2880, thus maintaining the steamin a vaporized state and at a relatively constant temperature. Invarious embodiments, the skeleton 2883 extends through a particularportion or the entire length of the catheter 2880. In one embodiment,the skeleton 2883 includes fins 2882 at regular intervals that keep theskeleton 2883 in the center of the catheter 2880 for uniform heating ofthe catheter lumen.

In another embodiment, as seen in FIG. 28C, the catheter includes aninner metal spiral 2888 in place of the skeleton. In yet anotherembodiment, as seen in FIG. 28D, the catheter includes an inner metalmesh 2889 in place of the skeleton. Referring to FIGS. 28B, 28C, and 28Dsimultaneously, water 2832 enters the luer lock 2849 at a predeterminedrate. It is converted to vapor 2838 in the heating chamber 2851. Themetal skeleton 2883, spiral 2888, and mesh 2889 all conduct heat fromthe heating chamber 2851 into the catheter lumen to prevent condensationof the vapor in the catheter and insure that ablating vapor will exitthe catheter from one or more holes or ports at its distal end.

FIG. 29 illustrates one embodiment of a heating unit 2990 usingmicrowaves 2991 to convert fluid to vapor in the vapor ablation systemof the present invention. The microwaves 2991 are directed toward thecatheter fluid heating chamber 2951, heating the chamber 2951 andconverting the fluid within into vapor. The vapor passes into thecatheter 2950 for use in the ablation procedure. A luer fitting coupler2949 is provided at the proximal end of the catheter fluid heatingchamber 2951 for connecting a tube supplying sterile water. In oneembodiment, a one-way valve (not shown) is included at the proximal endof the catheter fluid heating chamber 2951, distal to the luer fitting2949, to prevent the passage of vapor toward the water supply.

In various embodiments, other energy sources, such as, High IntensityFocused Ultrasound (HIFU) and infrared energy, are used to heat thefluid in the catheter fluid heating chamber.

One advantage of a vapor delivery system utilizing a heating coil isthat the vapor is generated closer to the point of use. Traditionalvapor delivery systems often generate vapor close to or at the point inthe system where the liquid is stored. The vapor must then travelthrough a longer length of tubing, sometimes over 2 meters, beforereaching the point of use. As a result of the distance traveled, thesystem can sometimes deliver hot liquid as the vapor cools in the tubingfrom the ambient temperature.

The device and method of the present invention can be used to causecontrolled focal or circumferential ablation of targeted tissue tovarying depth in a manner in which complete healing withre-epithelialization can occur. Additionally, the vapor could be used totreat/ablate benign and malignant tissue growths resulting indestruction, liquefaction and absorption of the ablated tissue. The doseand manner of treatment can be adjusted based on the type of tissue andthe depth of ablation needed. The ablation device can be used not onlyfor the treatment of Barrett's esophagus and esophageal dysplasia, flatcolon polyps, gastrointestinal bleeding lesions, endometrial ablation,pulmonary ablation, but also for the treatment of any mucosal,submucosal or circumferential lesion, such as inflammatory lesions,tumors, polyps and vascular lesions. The ablation device can also beused for the treatment of focal or circumferential mucosal or submucosallesions of any hollow organ or hollow body passage in the body. Thehollow organ can be one of gastrointestinal tract, pancreaticobiliarytract, genitourinary tract, respiratory tract or a vascular structuresuch as blood vessels. The ablation device can be placed endoscopically,radiologically, surgically or under direct visualization. In variousembodiments, wireless endoscopes or single fiber endoscopes can beincorporated as a part of the device. In another embodiment, magnetic orstereotactic navigation can be used to navigate the catheter to thedesired location. Radio-opaque or sonolucent material can beincorporated into the body of the catheter for radiologicallocalization. Ferro- or ferrimagnetic materials can be incorporated intothe catheter to help with magnetic navigation.

While the exemplary embodiments of the present invention are describedand illustrated herein, it will be appreciated that they are merelyillustrative. It will be understood by those skilled in the art thatvarious changes in form and detail may be made therein without departingfrom or offending the spirit and scope of the invention.

We claim:
 1. A vapor ablation system comprising: a container with asterile liquid therein; a pump in fluid communication with saidcontainer; a first filter disposed between and in fluid communicationwith said container and said pump; a heating component in fluidcommunication with said pump; a valve disposed between and in fluidcommunication with said pump and heating container; a catheter in fluidcommunication with said heating component, said catheter comprising atleast one opening at its operational end; and, a microprocessor inoperable communication with said pump and said heating component,wherein said microprocessor controls the pump to control a flow rate ofthe liquid from said container, through said first filter, through saidpump, and into said heating component, wherein said liquid is convertedinto vapor via the transfer of heat from said heating component to saidfluid, wherein said conversion of said fluid into said vapor results isa volume expansion and a rise in pressure where said rise in pressureforces said vapor into said catheter and out said at least one opening,and wherein a temperature of said heating component is controlled bysaid microprocessor.
 2. The vapor ablation system of claim 1, furthercomprising at least one sensor on said catheter, wherein informationobtained by said sensor is transmitted to said microprocessor, andwherein said information is used by said microprocessor to regulate saidpump and said heating component and thereby regulate vapor flow.
 3. Thevapor ablation system of claim 2, wherein said at least one sensorincludes one or more of a temperature sensor, flow sensor, or pressuresensor.
 4. The vapor ablation system of claim 1, further comprising ascrew cap on said liquid container and a puncture needle on said firstfilter, wherein said screw cap is punctured by said puncture needle toprovide fluid communication between said container and said firstfilter.
 5. The vapor ablation system of claim 1, wherein said liquidcontainer and said catheter are disposable and configured for a singleuse.
 6. The vapor ablation system of claim 1, wherein said liquidcontainer, first filter, pump, heating component, and catheter areconnected by sterile tubing and wherein the connections between saidpump and said heating component and said heating component and saidcatheter are pressure resistant.
 7. The vapor ablation system of claim1, further comprising a metal frame within said catheter, wherein saidmetal frame is in thermal contact with said heating component andconducts heat to said catheter lumen, thereby preventing condensation ofsaid vapor.
 8. The vapor ablation system of claim 7, wherein said metalframe comprises a metal skeleton with outwardly extending fins atregularly spaced intervals, a metal spiral, or a metal mesh and whereinsaid metal frame comprises at least one of copper, stainless steel, oranother ferric material.
 9. The vapor ablation system of claim 1,wherein said heating component comprises a heating block, wherein saidheating block is supplied power by said controller.
 10. The vaporablation system of claim 1, wherein said heating component uses one ofmagnetic induction, microwave, high intensity focused ultrasound, orinfrared energy to heat said fluid.